Got my HICTOP 3DP-18 and I wanted to share my build experience and some of the problems I stumbled upon. I reached a state where the printer seems to be working technically (all axis are moving, extruder and heated bed are heating correctly, fans are working and the filament is being extruded. Nothing is calibrated so I can't really print yet.

Main points I took from the build process:

Missing washers for M3 and M8 screws - especially important for the Y-Axis connecting threaded rods, the pressure can break the acrylic frame

I had a really tough time making the Y-Axis belt go straight without rolling over to the sides of the bearing and touching the bearing holder, I feel that the structure is not that solid and that I'm going to have to continue calibrating it.

The ball linear bearings are shitty - balls just started to drop when I moved them a bit. I actually bought high-quality LM8UU bearings but the printer uses a different model.

The end-stop cables are short and the connectors are 2-PIN JST when the motherboard connectors are 3-PIN JST - I had to try and connect them several times until I got it right (will upload motherboard pictures later)

I couldn't mount the filament monitor together with the filament holder, the holes in the frame are overlapping (or I might be missing something). Because the original firmware comes with the monitor enabled if you don't connect it you get an error that filament is missing, I uploaded Chip's modified code without that feature.

It was hard to load the filament, I had to disconnect the extruder fan and guide the filament into the hot-end by visually looking at it. I connected the fan again with the filament already loaded.

Seems like the auto PID tuning values from Chip's configuration aren't optimal for this model, I ran PID Autotune and after uploading it the printer heats correctly most of the time but fails every once in a while, will try to use Ultimaker default values and see how it goes.

Did you ever get new bearings or a new power supply. I have the 3DP-18 on order and it has not arrived yet but I am trying to do as much research about the build prior to it arriving. I purchased the auto level sensor but am now thinking about the bearings and PS as mentioned by you and Chip. Any suggestions as to size/model? Any other suggestions would be appreciated. Want this to go as smooth as possible.

I had a really tough time making the Y-Axis belt go straight without rolling over to the sides of the bearing and touching the bearing holder, I feel that the structure is not that solid and that I'm going to have to continue calibrating it.

I couldn't mount the filament monitor together with the filament holder, the holes in the frame are overlapping (or I might be missing something). Because the original firmware comes with the monitor enabled if you don't connect it you get an error that filament is missing, I uploaded Chip's modified code without that feature.

It was hard to load the filament, I had to disconnect the extruder fan and guide the filament into the hot-end by visually looking at it. I connected the fan again with the filament already loaded.

I Have a 3DP11 and 12
I also had troubles aligning the Y axis, Then I found these MF128ZZ 8 X 12 X 3.5 Flanged Bearings. They are half width bearings, the Belt will run between the Flanges of two placed with the Flanges facing outwards on the 8MM bolt. Now the belt never rubs the Y Axis frame, same Ideal as the X_Axis belt assembly.

Could not get my filament monitor to work tried every pin re-flashed every option everyone suggested, until I decided try to wire it into the unused X_Max pin and Connector and can't remember where I read it to thank them.

Filament is definitely fun to load on this style Extruder. I have to straighten the filament then hold it perfectly straight above like i'am threading a needle. Thought about using a pencil sharpener to give the Filament a point.